lit/lit lit-html@2.0.0

on GitHub

Major Changes

• The templateFactory option of RenderOptions has been removed.

• TemplateProcessor has been removed.

• Symbols are not converted to a string before mutating DOM, so passing a Symbol to an attribute or text binding will result in an exception.

• The shady-render module has been removed and is now part of platform-support, and Lit's polyfill support now adds the following limitations: (1) Bindings in style elements are no longer supported. Previously these could not change and in the future they may be supported via static bindings. (2) ShadyCSS.styleElement is no longer called automatically. This must be called whenever dynamic changes that affect styling are made that involve css custom property shimming (older browsers) or changes to custom properties used via the deprecated @apply feature. It was previously called only on first render, and it is now up to the user to decide when this should be called. See Polyfills for more details.

• render() no longer clears the container it's rendered to. It now appends to the container by default.

• Expressions in comments are no longer rendered or updated. See Valid expression locations for more details.

• Template caching happens per callsite, not per template-tag/callsize pair. This means some rare forms of highly dynamic template tags are no longer supported.

• Arrays and other iterables passed to attribute bindings are not specially handled. Arrays will be rendered with their default toString representation. This means that html`<div class=${['a', 'b']}> will render <div class="a,b"> instead of <div class="a b">. To get the old behavior, use array.join(' ').

• Multiple bindings in a single attribute value don't require the attribute value is quoted, as long as there is no whitespace or other attribute-ending character in the attribute value. html`<div id=${a}-${b}>`

• The directive and part APIs are significantly different. See Custom Directives and the Upgrade Guide for more details.

• The Directive base class and directive() factory function are
  now exported from the lit-html/directive.js module.

• NodePart has been renamed to ChildPart,
  along with other methods and variables that use the "Node" naming, like
  PartType.Node which is now PartType.CHILD.

• The part exports (ChildPart,
  AttributePart, etc) have been change to interface-only exports. The constructors are no longer exported. Directive authors should use helpers in directive-helpers.js to construct parts.

• The eventContext render option has been changed to host.

• #2103 15a8356d - Updates the exports field of package.json files to replace the subpath
  folder
  mapping
  syntax with an explicit list of all exported files.

  The /-suffixed syntax for subpath folder mapping originally used in these
  files is deprecated. Rather than update to the new syntax, this change replaces
  these mappings with individual entries for all exported files so that (a) users
  must import using extensions and (b) bundlers or other tools that don't resolve
  subpath folder mapping exactly as Node.js does won't break these packages'
  expectations around how they're imported.

• #1764 0b4d6eda - Don't allow classMap to remove static classes. This keeps classMap consistent with building a string out of the classnames to be applied.

Minor Changes

• Added renderBefore to render options. If specified, content is rendered before the node given via render options, e.g. {renderBefore: node}.
• Added development mode, which can be enabled by setting the development Node exports condition. See Development and production builds for more details.
• All usage of instanceof has been removed, making rendering more likely to
  work when multiple instances of the library interact.
• Template processing is more robust to expressions in places other than text and attribute values.
• render now returns the ChildPart that was created/updated by render.
• Added AsyncDirective, which is a Directive subclass whose
  disconnected callback will be called when the part containing the directive
  is cleared (or transitively cleared by a Part higher in the tree) or manually
  disconnected using the setConnected API, and whose reconnected callback
  will be called when manually re-connected using setConnected. When
  implementing disconnected, the reconnected callback should also be
  implemented to return the directive to a usable state. Note that LitElement
  will disconnect directives upon element disconnection, and re-connect
  directives upon element re-connection. See Async directives for more details.
• Added setConnected(isConnected: boolean) to ChildPart; when called with
  false, the disconnected callback will be run on any directives contained within
  the part (directly or transitively), but without clearing or causing a
  re-render to the tree. When called with true, any such directives'
  reconnected callback will be called prior to its next update/render
  callbacks. Note that LitElement will call this method by default on the
  rendered part in its connectedCallback and disconnetedCallback.
• Added the static-html module, a static html tag function, a literal tag function, and unsafeStatic(), which allows template authors to add strings to the
  static structure of the template, before it's parsed as HTML. See Static expressions for more details.
• Added lit-html/directive-helpers.js module with helpers for creating custom directives. See Custom directives for more details.
• Rendering null, undefined, or empty string in a ChildPart now has the same affect as rendering nothing: it does not produce an empty text node. When rendering into an element with Shadow DOM, this makes it harder to inadvertently prevent <slot> fallback content from rendering.
• Nested directives whose parent returns noChange are now unchanged. This
  allows the guard directive to guard directive values (#1519).
• Added optional creationScope to RenderOptions, which controls the node from which the template is cloned from.
• Added support for running with Trusted Types enforced.

Patch Changes

• #1922 8189f094 - Binding noChange into an interpolated attribute expression now no longer removes the attribute on first render - instead it acts like an empty string. This is mostly noticable when using until() without a fallback in interpolated attributes.

• #1964 f43b811 - Don't publish src/ to npm.

• #2070 a48f39c8 - Throw instead of rendering an innocuous value into a style or script when security hooks are enabled.

• #2044 662209c3 - Improves disconnection handling for first-party AsyncDirectives (until, asyncAppend, asyncReplace) so that the directive (and any DOM associated with it) can be garbage collected before any promises they are awaiting resolve.